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1.1 root 1: /*
2: Hatari - low320x16_spec.c
3:
1.1.1.2 root 4: This file is distributed under the GNU General Public License, version 2
5: or at your option any later version. Read the file gpl.txt for details.
1.1 root 6:
7: Screen Conversion, Low Res Spec512 to 320x16Bit
8: */
9:
10: static void ConvertLowRes_320x16Bit_Spec(void)
11: {
12: Uint32 *edi, *ebp;
13: Uint16 *esi;
14: Uint32 eax, ebx, ecx, edx;
15: Uint32 pixelspace[5]; /* Workspace to store pixels to so can print in right order for Spec512 */
16: int y, x;
17:
18: /* on x86, unaligned access macro touches also
19: * next byte, zero it for code checkers
20: */
21: pixelspace[4] = 0;
22:
23: Spec512_StartFrame(); /* Start frame, track palettes */
24:
25: for (y = STScreenStartHorizLine; y < STScreenEndHorizLine; y++)
26: {
27:
28: Spec512_StartScanLine(); /* Build up palettes for every 4 pixels, store in 'ScanLinePalettes' */
29:
30: /* Get screen addresses, 'edi'-ST screen, 'ebp'-Previous ST screen, 'esi'-PC screen */
31: eax = STScreenLineOffset[y] + STScreenLeftSkipBytes; /* Offset for this line + Amount to skip on left hand side */
32: edi = (Uint32 *)((Uint8 *)pSTScreen + eax); /* ST format screen 4-plane 16 colors */
33: ebp = (Uint32 *)((Uint8 *)pSTScreenCopy + eax); /* Previous ST format screen */
34: esi = (Uint16 *)pPCScreenDest; /* PC format screen */
35:
36: x = STScreenWidthBytes >> 3; /* Amount to draw across in 16-pixels (8 bytes) */
37:
38: do /* x-loop */
39: {
40: ebx = *edi; /* Do 16 pixels at one time */
41: ecx = *(edi+1);
42:
43: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
44: /* Convert planes to byte indices - as works in wrong order store to workspace so can read back in order! */
45: LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [12,13,14,15] */
46: pixelspace[3] = ecx;
47: LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [4,5,6,7] */
48: pixelspace[1] = ecx;
49: LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [8,9,10,11] */
50: pixelspace[2] = ecx;
51: LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [0,1,2,3] */
52: pixelspace[0] = ecx;
53: #else
54: LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [4,5,6,7] */
55: pixelspace[1] = ecx;
56: LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [12,13,14,15] */
57: pixelspace[3] = ecx;
58: LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [0,1,2,3] */
59: pixelspace[0] = ecx;
60: LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [8,9,10,11] */
61: pixelspace[2] = ecx;
62: #endif
63: /* And plot, the Spec512 is offset by 1 pixel and works on 'chunks' of 4 pixels */
64: /* So, we plot 1_4_4_4_3 to give 16 pixels, changing palette between */
65: /* (last one is used for first of next 16-pixels) */
66: ecx = pixelspace[0];
67: PLOT_SPEC512_LEFT_LOW_320_16BIT(0);
68: Spec512_UpdatePaletteSpan();
69:
70: ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 1);
71: PLOT_SPEC512_MID_320_16BIT(1);
72: Spec512_UpdatePaletteSpan();
73:
74: ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 5);
75: PLOT_SPEC512_MID_320_16BIT(5);
76: Spec512_UpdatePaletteSpan();
77:
78: ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 9);
79: PLOT_SPEC512_MID_320_16BIT(9);
80: Spec512_UpdatePaletteSpan();
81:
82: ecx = GET_SPEC512_OFFSET_FINAL_PIXELS(pixelspace);
83: PLOT_SPEC512_END_LOW_320_16BIT(13);
84:
85: esi += 16; /* Next PC pixels */
86: edi += 2; /* Next ST pixels */
87: ebp += 2; /* Next ST copy pixels */
88: }
89: while (--x); /* Loop on X */
90:
91: Spec512_EndScanLine();
92:
93: /* Offset to next line */
94: pPCScreenDest = (((Uint8 *)pPCScreenDest) + PCScreenBytesPerLine);
95: }
96:
97: bScreenContentsChanged = true;
98: }
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